# TODO str.isalpha() 判断字符串是纯字母组成
a = 'dff'
print(a.isalpha())   # True
a = 'd1f'
print(a.isalpha())   #False

# TODO str.isalnum 判断字符串是纯字母数字组成
a1 = 'd1f'
print(a1.isalnum ())  # False
# TODO str.islower() 判断字符串都是小写字母
a2= 'Hello'
print(a2.islower ())   # True

# TODO str.isspace() 判断字符串是空格 \t
str4 = ' '
print(str4.isspace())   # True
str5 = '\t'
print(str5.isspace())  # True
str6 = '\n'
print(str6.isspace())      # True
str7 = 'a '
print(str7.isspace())       # False
str8 = ''
print(str8.isspace())         # False
